COMPOSITION OF SEMI-SYNTHETIC CUTTING OIL FOR METAL WORKING APPLICATIONS

Abstract

The invention relates to an semi-synthetic cutting oil composition comprising high viscosity index spindle oil, emulsifiers and other performance additives like EP, corrosion inhibitors and biocides etc.. The composition forms translucent emulsion with water and it can be employed for metalworking operations. The said composition is particularly suitable for grinding, milling, drilling, turning operations. It has excellent hard water stability, swarf removal and cooling characteristics. It also has very good emulsion stability, corrosion protection properties and bio-stability.

"Composition of Semi-synthetic Cutting Oil For Metal Working
Applications"
INDIAN OIL CORPORATION LIMITED of the address: G-9, AN Yavar Jung Marg, Bandra (East), Mumbai-400051
The following specification particularly describes and ascertains the nature of this invention and the manner in which it has to be performed.

Introduction-
The invention relates to an semi-synthetic cutting oil composition comprising high viscosity index spindle oil, emulsifiers and other performance additives like EP, corrosion inhibitors and biocides and the like. The composition forms translucent emulsion with water and it can be employed for metalworking operations. The said composition is particularly suitable for grinding, milling, drilling, turning operations. It has excellent swarf removal and cooling characteristics. It also has very good corrosion protection properties, emulsion stability, bio-stability.
DESCRIPTION
Field of the Invention
The present invention relates to a semi-synthetic cutting oil composition comprising high viscosity spindle oil, suitable emulsifiers and other performance additives. The composition described in the present invention relates to the composition of an emulsified high viscosity spindle oil, which forms translucent emulsion with water and is useful for various metalworking applications and particularly cutting operations like grinding, milling, drilling, turning etc.
PRIOR ART
Today, the soluble cutting oils market has increased manifold in size and a variety of such oils are being used in a large number of applications. Although, soluble cutting oils are used by various manufacturing industries, but oil specifications are scanty in the cutting fluid area and, generally, oil performance is governed by customer assessment of performance and OEM specifications in most of the cases. Traditionally, soluble cutting oils are still holding the largest share, but their market has been witnessing continuous changes in perception and practices over the past few years and now high
quality, high cost and high performance semi-synthetic cutting oils have penetrated into
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the market place. The driving force for acceptability and use of high cost semi synthetic cutting oils is longer sump life, high performance, cleanliness etc. Use of these oils reduces the performance hassles and enables trouble free operation for the production units. These oils are optimized combination of chemical constituents and oil. They have lower oil content but contain more emulsifier and performance chemicals. These oils have moderate lubrication, high cooling efficiency, high rust inhibition and excellent cleanliness properties. Sulfur, chlorine, and phosphorous, esters type additives are also added to these oils to improve the extreme pressure/anti wear/lubricity characteristics. These products are ideally suited for both ferrous and non-ferrous type applications.
A variety of chemicals, additives and surfactants have been used to formulate the semisynthetic cutting oils. Some of the common ingredients are base oils, polyolesters, sodium petroleum sulphonates, salts of fatty acids, nonionic surfactants, ethanol amines, sulphurised fatty material, fatty acid esters, chlorinated paraffin, fatty alcohols, hindered phenols, borate, biocides, odorizing agent, azo dyes, alkali etc. The composition of semi-synthetic cutting oils is specific for each company due to complexity of the formulations and possibility of a large number of permutation and combinations. Most recent compositions to some of the oldest of the semi-synthetic compositions, as reported in literature are listed below:
Water-based metal-working lubricants containing an emulsion-type anionic, soluble oil comprising a low viscosity index (LVI) lubricating oil, sodium sulfonates as an emulsifier, a soluble oil co-emulsifier base containing naphthenic acids, potassium hydroxide, anti-rust and anti-microbial agents and an effective amount of block copolymers of ethylene oxide and propylene oxide or other alkylene oxides having a molecular weight between about 800 and about 8,000 is reported by Shell Oil Company (US 4,414,121). Workers have reported reported (US 4,440,654) a method for producing a cooling emulsion, particularly for use as an auxiliary means in boring, cutting and grinding in the metalworking industry, in which organic substances which are per se insoluble in water are rendered water-dispersible and are emulsified with water. A mixture of about 3% to 15% by weight of natural wax(es) of animal and/or 0.1% to 0.45% by weight of a
commercial emulsifier, and the remainder an aqueous di/tri-ethanol mixture comprising
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about 50% by weight of water, 37.5% by weight of di-ethanolamine and about 12.5% by
weight of tri-ethanolamine is produced. Then the mixture is brought to a boil while
stiring; after dissolution of the wax component, it is cooled to a reaction temperature
while stirring, and subsequently, after aminization of the wax component by the
di/triethanol mixture is cooled down to application temperature. For use it is further
diluted with water. A cutting oil suitable for the working of nonferrous metals, in
particular for milling and engraving copper cylinders employed in gravure printing, is
based on fatty acid esters of monohydric or polyhydric alcohols in an organic solvent
which is selected from glycols, oligoglycols, polyglycols or their monoethers, diethers,
monoesters or diesters, and also contains a surfactant, preferably an anionic surfactant
is reported by Merck Patent Gesellschaft (US 4,578,202). A composition for the
preparation of a soluble-oil for use in a cutting fluid comprises a mineral oil and, as an
emulsifier, an effective amount of a sulphonate of a branched polymer of C3 to C5 olefin.
Preferably the polyolefin chain of the sulphonate has an average molecular weight in
the range 275 to 560 and the polyolefin is polyisobutene is disclosed by The British
Petroleum Company (US 4,778,614). A soluble-oil can be prepared from the above
composition by the addition of a conventional corrosion inhibitor and diluted with water
to make a cutting fluid. Advantages of the novel emulsifier are that they are resistant to
breakdown by micro-organisms and do not require the addition of a coupling agent. A
metalworking lubricant comprising an oil-in-water microemulsion and containing about
1-30 wt % natural or synthetic oil; about 0.5-30 wt % of a water-soluble surfactant,
preferably a nonionic surfactant; about 1-20 wt % of an organic co-surfactant, preferably
1,2-octanediol; and about 45-97.5 wt % water containing less than about 1 wt %
dissolved inorganic salts is patented by Aluminum Company of America (US
4,781,848). Aluminum Company of America (US 4,781,849) has also disclosed a
metalworking lubricant comprising about 1-20 wt % natural or synthetic oil; about 0.5-30
wt % of a water-soluble surfactant, preferably a nonionic surfactant; about 1-20 wt % of
an organic co-surfactant, preferably 1,2-octanediol; and about 50-97.5 wt % water
containing less than about 1 wt % dissolved inorganic salts. The lubricant is preferably a
lyotropic liquid crystal. Exxon Chemical Patents Inc. (US 4,956,110) has disclosed the
use of a water-soluble hydroxyl di- or tri-carboxylic acid, generally in combination with
an alkanolamine in an oil water fluid especially metal working or hydraulic fluids results
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in a fluid having excellent hard water compatibility, low foaming tendency in soft water and a good biostability; other additives such as emulsifiers, copper passivators and the like generally present. Workers of Idemitsu Kosan Company Limited have disclosed (US 4,946,612)is a lubricating oil composition both for lubrication of sliding surface of machine tools and for lubrication of working part of machine tools which is free from the conventional problems. This composition comprises a reaction product of a dibasic acid of 16-24 carbon atoms with a piperazine compound, a lubricating oil, an emulsifier and, if necessary, an extreme pressure agent and/or an oiliness agent. The Nisshin Oil Mills, Ltd. and Nippon Steel Corporation have disclosed (US 4,956,109) a lubricating oil comprising at least one member selected from the group consisting of esterified products obtained by reacting: (A) a compound selected from the group consisting of alcohols represented by the following general formula (I), alcohols represented by the following general formula (II) and hydrogenated derivatives thereof; with (B) a fatty acid having not less than 6 carbon atoms or a mixture of the fatty acid with a rosin selected from the group consisting of rosin, hydrogenated rosins, disproportionated rosins and polymerized rosins. The lubricating oil is used as rolling mill oils, hydraulic oils cutting-grinding oils, lubricating oils for metal plastic working and those for internal combustion engines. An invention relating to a water-soluble lubricant composition for a sleeve surface lubricating oil, an operating fluid, a cutting oil, a rolling oil, a drawing oil, a press oil or the like, which does not pollute the environment and has superior lubricity, metal corrosion preventing property, antifoaming property and antiseptic property is disclosed by Yushiro Chemical Industry Co., Ltd. (US 5,322,631). The water-soluble lubricant composition of this invention containing surfactants (a) and one or two salts (b) selected from among carboxylates and sulfonates is characterized in that the above one or two salts (b) selected from among carboxylates and sulfonates are alkaline earth metal salts or zinc salts and that substantially no nitrogen ingredients are contained and the amount of nitrogen contained represents its amount in impurities, or 0.5 wt % or below of nitrogen. Mobil Oil Corporation has disclosed (US 5,417,869) bio-resistant surfactants and cutting fluid compositions which utilize them. The surfactants consist of soaps of carboxylic acid compounds having from 10 to 30 carbon atoms, the carbon skeleton of which is branched and not straight chain. It is the branching which lends the resistance
to biodegradation to the products of the invention. Further enhanced bio-resistance may
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be obtained by utilizing a branched lubricating base stock material in the cutting fluid composition. Berol Nobel AB and Castrol Ltd. have disclosed a method (US 5 533,431) of producing an amide product mixture having a low content of secondary amines by reacting an amide product mixture having a high secondary amine content with an aliphatic alkylene oxide in the absence of an essential amount of any alkoxylation catalyst. The amide product mixture obtained contains a minor amount of tertiary amines and exhibits advantageous properties when used for the formulation of cosmetic products, such as shampoos and creams; foam cleaning compositions, e.g. for textiles and cars; and functional fluids, such as lubricants, metal working fluids and hydraulic fluids. A method of producing water-soluble cutting fluid is disclosed (US 5,693,596). The soluble cutting oil is produced by dissolving a polymer fatty acid triglyceride imidazole, 2-methyl-1-stearate, and boric acid imidazole in the dispersion of inorganic bentonite in water thereby preparing a main component and adding oleic acid (agent for enhancing the lubricity), Na salt of ethylenediamine tetraacetic acid (metallic ion adsorbent), benzotriazole (rust-preventing auxiliary agent), and a silicone type defoaming agent to the main component. Nalco Chemical Company has disclosed an additive composition for metal-working fluids and a method for producing the additive composition (US 5,866,521). The additive composition comprises from about 0.01 to about 25.0 mole weight of iso-stearic acid to 2-amino-2-methyl-1-propanol whereby a salt of iso-stearic acid-2-amino-2-methyl-1-propanol is formed. The metal-working fluid composition comprises from about 0.01 to about 40 percent by weight of iso-stearic acid-2-amino-2-methyl-1-propanol salt and from about 99.99 to about 60 percent by weight of a synthetic or semi-synthetic metal-working fluid. Dainippon Ink and Chemicals, Inc. has disclosed a sulfur-based extreme-pressure additive (US 6,413,917) that is completely soluble in water without using a surfactant, and has satisfactory odor and hue. In addition, the present invention provides a cutting liquid and grinding liquid having superior defoaming property and rust preventive characteristics, while also having high load resistance and lubrication performance comparable to cutting oils and grinding oils of the prior art. The above objects are achieved by an extreme-pressure additive comprising the salt of a condensation product of a sulfurized hydroxy-unsaturated fatty acid, the condensation product having a sulfur content of 8 to 15% by
weight (mass), color of 6 or less, and acid value of 80 to 200, and a grinding liquid
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comprising that extreme-pressure additive and water. Similarly, Ajinomoto Co., Inc. has patented a cutting oil composition(US 6,605,575), which is excellent in solubility, lubricity, cutting properties, antirust ability, safety, and washing ability and reduced in foaming, and for that purpose, an N-acylamino acid having a long chain acyl group and/or a salt thereof, or an N-alkylamino acid having a long chain alkyl group and/or a salt thereof is used concurrently with an alkylalkylene oxide and/or an acylalkylene oxide. A lubricant composition comprises (1) at least one member selected from the group consisting of carboxylic acid compounds each obtained by the addition of an oxyalkylene group to a hydroxyl group of a hydroxy carboxylic acid and alkali metal salts and amine salts thereof; and (2) at least one base oil selected from the group consisting of alkyl benzene, normal paraffin, isoparaffin and .alpha.-olefin is disclosed (US 6,525,006). The lubricant composition is highly resistant to putrefaction when it is used as a metal-processing oil composition and shows excellent cutting characteristics in the metal-processing, which requires an extremely high lubricating action, such as form-rolling tap and deep hole boring. Moreover, the composition makes operations such as metal-processing operations easy since the liquid obtained by diluting it with water is transparent or translucent. Henkel Kommanditgesellschaft auf Aktien has patented a process (US 6,705,142) for the cutting or non-cutting forming of metals using two cooling lubricants, wherein an oil or a first emulsion having an oil content of at least 10 wt. % is applied to the workpiece, as a first cooling lubricant, at the tribo-zone and, at the same time, an oil-free cooling lubricant or a second emulsion that is an oil-in-water emulsion having an oil content of less than 10 wt. % is applied, as a second cooling lubricant, adjacent to the tribo-zone. Depending on the metal-working technique, a two-component nozzle is preferably used for supplying the first and second cooling lubricants, the jet of second cooling lubricant surrounding the jet of first cooling lubricant concentrically. Alternatively, it is possible to supply the first cooling lubricant directly to the tribo-zone through channels in the tool, while the second cooling lubricant is applied at the periphery. The cooling lubricants that run off are together fed to a storage container, where phase separation of the first and second cooling lubricants takes place. A device for carrying out the process having two storage containers, wherein, in order to complete the phase separation, the phase of the first cooling lubricant
separated out in the first container is transferred into the second container. A stable,
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clear water-in-oil emulsion consisting of from about 5 to about 40 wt % aqueous phase and from about 95 to about 60 wt % non-aqueous phase, said aqueous phase being dispersed in said non-aqueous phase in the form of droplets having an average droplet size no greater than about 0.1 .mu.m, said emulsion comprising at least 60 wt % of an oil selected from fuel oils, lubricating oils and mixtures thereof, from about 5 to about 30 wt % of an emulsifier composition, and the balance to 100 wt % water, wherein said emulsifier composition consists essentially of i) a mixture of C.sub.6 -C.sub. 15 alcohol ethoxylates, each comprising from 2 to 12 EO groups, ii) from 0 to about 25 wt % of an emulsifier selected from polyisobutylsuccinimide, a sorbitan ester and mixtures thereof, and iii) from 0 to about 90 wt % of an amine ethoxylate. The microemulsion is useful as a fuel and/or lubricant/coolant(US 6,716,801). Recently, Nippon Mitsubishi Oil Corporation has disclosed cutting or grinding oil compositions(US 6,858,569), which are suitable for use in a minimal quantity lubrication system in which a minimal quantity of an oil is supplied to the spot to be cut or ground of a work, together with air are reduced in stickiness and improved in lubricity.
Efforts have therefore, made to develop a semi-synthetic cutting oil for metal working applications.
Therefore, an object of this invention is to propose a semi-synthetic cutting oil composition, which is used as oil in water emulsion for metal working operations.
Another object of this invention is to propose a semi-synthetic cutting oil composition that can advantageously be used to give excellent hard water stability and can easily withstand 1000 ppm hardness of water when calculated in terms of calcium carbonate and forms translucent emulsion when mixed with water.
Yet another object of this invention is to propose a soluble cutting oil composition, which can give longer emulsion/sump life and excellent pH stability during use.
A further object of this invention is to propose a semi-synthetic cutting oil composition
which when used in metal working operations, provides very good rust protection.
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A still further object of this invention is to propose a semi-synthetic cutting oil composition which when used in metal working application, provides excellent bacterial resistance and also retard bacterial growth, thus increasing the serviceable life of the emulsion.
Yet another object of this invention is to propose a semi-synthetic cutting oil composition having low content of cost intensive materials.
Another object of this invention is to propose a semi-synthetic cutting oil composition, which has excellent swarf removal characteristics during metal working operations.
A further object of this invention is to propose a semi-synthetic cutting oil composition which gives excellent surface finish to work piece in metal cutting operations like grinding, milling, turning, drilling, etc.
A still further object of this invention is to propose a semi-synthetic cutting oil composition, which allows tool and work piece visibility to operator during machining operation, due to translucent nature of the emulsion.
Background of the invention
This invention relates to the development of semi-synthetic cutting oil for metal working applications.
Metal cutting fluids are traditionally classified according to their composition and are
classified as neat oil, soluble oil, semi-synthetic fluid, or synthetic fluid. Semi-synthetic
cutting oils contain appreciable amount of water and are provided to the end user as an
oil containing specialty additives. These oils are a combination of highly refined mineral
oil, and tailoade additive systems and substantial amount of water. These oils require
high amount of emulsifier additives as these are basically in the form of micro-emulsion
and form translucent emulsion with water. The emulsifier additives adsorb over oil
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globules and help in dispersing oil in water phase. The fluid concentrate usually includes other additives such as chlorinated or sulfurized mineral oils, fatty oils, or mixtures thereof, biocides, corrosion/rust inhibitors etc. to improve performance and lengthen the life of the fluid. Semi-synthetic cutting oils provide good lubrication characteristics. In addition, they provide excellent cooling characteristics also. Emulsions of these oils provide longer sump life and enhanced bacterial resistance. Due to low oil content and good amount of performance chemicals at times these oils give better performance over simple soluble type cutting oils where the oil content is more than 80-90% in the formulation. Semi-synthetic cutting oil generally form translucent emulsions, therefore they provide excellent visibility of tool and work piece to the operator.
Formulations of metal working oils are quite complex. Metal working oils in general constitute an area of lubrication technology where chemistry is very much in action in the whole application regime. The performance or non-performance of a metal working fluid becomes quickly evident during its use. Unlike other industrial oil lubricants, where the performance of the oil will be known only after some time, the performance of metalworking oil will become evident as soon as it is put into the machining operation. Situation is more critical in the case of water mixed soluble type of oils. A defect in a soluble oil, for example cutting oil or rolling oil, will show up in a couple of days if not earlier and will call for quick corrective action. The factors affecting the performance of these oils are multi faceted; therefore, these oils require special attention of the formulator as well as user. Performance of the same oil may vary significantly from one use to other depending upon the application, metallurgy and maintenance practices etc.
Keeping in view of all the above properties of semi-synthetic cutting oil composition, a developmental program was initiated. Therefore, the present invention describes a composition of semi-synthetic cutting oil. A large number of chemicals, additives were used in the development of semi-synthetic cutting oil.
Summary of the Invention
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The semi-synthetic cutting oil composition disclosed in the present invention is an optimised combination of high viscosity spindle oil, water, emulsifiers such as sodium petroleum sulphonate, tri-ethanolamine oleate, biocide, a fatty acid diethanolamide, buffering agent etc.
The semi-synthetic cutting oil of the present invention forms translucent emulsion when mixed with water. The emulsion so formed can be employed for various metal working operations particularly metal cutting operations like grinding, milling, turning, drilling etc. The semi synthetic cutting oil composition provides longer emulsion life and very good bacterial resistance, besides providing other performance benefits like cooling, swarf removal and corrosion protection etc.
Detailed Description
The semi-synthetic cutting oil composition disclosed in the present invention includes water, high viscosity spindle oil sodium petroleum sulphonate, tri-ethanolamine, oleic acid, a fatty acid diethanolamide, a triazine derivative and boric acid to get the high hard water emulsion stability, good bio-stability and excellent corrosion protection. Preferred concentrations of the high viscosity index spindle oil is 13.6 to 29.1 wt%, fatty acid diethanol amide is 3.1 to 12.0 %, concentration of oleic acid is 1.2 to 8%, concentration of tri-ethanolamine is 5.4 to 14.8%, concentration of sodium petroleum sulphonate is 4.2 to 6.8%, concentration of boric acid is 0.5 to 3.0%, concentration of triazine derivative type biocide is 1.4 to 2.4%, concentration of water is 35.2 to 56.2% respectively in the final composition of the disclosed semi synthetic cutting oil. However, a stable formulation can not be obtained without a co-solvent like lauryl alcohol is present in the range of 0.9 to 4.1 %wt.
The process of evaluating and identifying a preferred composition of semi-synthetic cutting oil is further described below:
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EXPERIMENTAL DESCRIPTION
In order to establish the suitability of the developed semi-synthetic cutting oil, a number of compositions using various components comprising base oils, emulsifiers, corrosion inhibitors, co-solvents, biocides etc. were prepared and evaluated for thermal stability and emulsion stability tests.
It can be appreciated that only combination of emulsifiers and high viscosity spindle oil is not sufficient for making good quality semi-synthetic cutting oil. Therefore, a optimised combination of the emulsifiers and other performance additives was selected based on the chemistry and nature of the emulsifiers to get a composition of semi-synthetic cutting oil.
In order to make different semi-synthetic cutting oil compositions, the high viscosity spindle oil was taken in a beaker and heated to 30 to 35 deg.C. and emulsifier additives were added to it. This mixture was thoroughly mixed and co-solvent, biocide, were also added. Lastly a solution of boric acid in water was added gradually with constant stirring to obtain the semi-synthetic cutting oil blend. The blends showing separation were not evaluated further. The clear blends showing good emulsion stability were for other properties like cast iron corrosion, thermal stability, frothing test etc. The formulation/s meeting all the laboratory test requirements were subjected to tapping efficiency test also and the best performing formulation was selected.
Results of various experiments carried out are given below in example 1 to example 15.
Chemical names of the compounds are as follows:

hardness water At Dilution, 50 : 1
Example 8
In order to improve upon cast iron corrosion characteristics, a new additive Hostacor B was used. Semi-synthetic cutting oil blends were prepared by changing concentration of Hostacor B in blend 29 to blend 32. All the blends have shown poor cast iron corrosion characteristics.

35.2 to 56.2% respectively in the final composition of the semi synthetic cutting oil composition. However, best results are obtained when the concentrations of the high viscosity index spindle oil is 15.0 to 25.0 wt%, fatty acid diethanol amide is 5.0 to 10.5.0 %, concentration of oleic acid is 2.0 to 6.0%, concentration of tri-ethanolamine is 7.0 to 13.0%, concentration of sodium petroleum sulphonate is 4.2 to 6.5%, concentration of boric acid is 0.8 to 2.4%, concentration of lauryl alcohol is 1.2 to 3.5% , concentration of triazine derivative type biocide is 1.4 to 2.1%, concentration of water is 39.0 to 52.0% respectively.
The above composition forms translucent emulsion with water having pH value of 8.2 to 9.1. The composition of semi-synthetic cutting oil was further evaluated on bio-stability and tapping efficiency tests and has given excellent results in both the rig tests. The composition was also evaluated in field for grinding, milling, turning, drilling etc. operations and has given excellent results with respect to emulsion stability, longer emulsion life, bio-stability and pH control during use. The operators were able to see the work piece and tool due to translucent nature of the emulsion.
Having described the techniques of the present invention, it can be appreciated that the semi-synthetic cutting oil as claimed is manufactured using unique combination of the carefully selected high viscosity spindle oil, emulsifiers and other performance additives. The semi-synthetic cutting oil composition described in this invention is a novel product forming translucent emulsion with water and is suitable for various metal working operation particularly cutting operations in manufacturing industries. However, the examples discussed here are only illustrative examples and should not be interpreted in a limiting senesce.
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2. The semi -synthetic cutting oil composition as claimed in claim 1 wherein the concentration of high viscosity index spindle oil is 15.0 to 25.0 wt %.
3. The semi -synthetic cutting oil composition as claimed in claim 1 wherein the concentration of fatty acid diethanol amide is 3.1 to 12.0%.
4. The semi -synthetic cutting oil composition as claimed in claim 1 wherein the concentration of oleic acid is 2.0 to 6.0%.
5. The semi -synthetic cutting oil composition as claimed in claim 1 wherein the concentration of tri-ethanolamine is 7.0 to 13.0%.
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6. The semi -synthetic cutting oil composition as claimed in claim 1 wherein the concentration of sodium petroleum sulphonate is 4.2 to 6.5%.
7. The semi -synthetic cutting oil composition as claimed in claim 1 wherein the concentration of lauryl alcohol is 1.2 to 3.5%.
8. The semi -synthetic cutting oil composition as claimed in claim 1 wherein the concentration of triazine derivative type biocide is 1.4 to 2.1%.
9. The semi -synthetic cutting oil composition as claimed in claim 1 wherein the concentration of water is 39.0 to 52.0%.
10. The semi -synthetic cutting oil composition as claimed in claim 1 wherein the alkanol amine is selected from di-ethanolamine, mono-ethanolamine and tri-ethanolamine.
11. The semi -synthetic cutting oil composition as claimed in claim 1 wherein the boric acid amine complex is used as a buffering agent.
12. The semi -synthetic cutting oil composition as claimed in claim 1 wherein emulsion formed with said composition gives excellent hard water stability and bio-stability.

13.A semi -synthetic cutting oil composition for metal working applications
substantially as herein described with reference to the foregoing description,
examples and tables.
Dated this 6th day of March 2006 SHARADVADEHRA

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ABSTRACT
TITLE: COMPOSITION OF SEMI-SYNTHETIC CUTTING OIL FOR METAL WORKING APPLICATIONS
The invention relates to an semi-synthetic cutting oil composition comprising high viscosity index spindle oil, emulsifiers and other performance additives like EP, corrosion inhibitors and biocides etc.. The composition forms translucent emulsion with water and it can be employed for metalworking operations. The said composition is particularly suitable for grinding, milling, drilling, turning operations. It has excellent hard water stability, swarf removal and cooling characteristics. It also has very good emulsion stability, corrosion protection properties and bio-stability.
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